Pollan (The Botany of Desire ) examines what he calls "our national eating disorder" (the Atkins craze, the precipitous rise in obesity) in this remarkably clearheaded book. It's a fascinating journey up and down the food chain, one that might change the way you read the label on a frozen dinner, dig into a steak or decide whether to buy organic eggs. You'll certainly never look at a Chicken McNugget the same way again.

Pollan approaches his mission not as an activist but as a naturalist: "The way we eat represents our most profound engagement with the natural world." All food, he points out, originates with plants, animals and fungi. "[E]ven the deathless Twinkie is constructed out of... well, precisely what I don't know offhand, but ultimately some sort of formerly living creature, i.e., a species . We haven't yet begun to synthesize our foods from petroleum, at least not directly."

Pollan's narrative strategy is simple: he traces four meals back to their ur-species. He starts with a McDonald's lunch, which he and his family gobble up in their car. Surprise: the origin of this meal is a cornfield in Iowa. Corn feeds the steer that turns into the burgers, becomes the oil that cooks the fries and the syrup that sweetens the shakes and the sodas, and makes up 13 of the 38 ingredients (yikes) in the Chicken McNuggets.

Indeed, one of the many eye-openers in the book is the prevalence of corn in the American diet; of the 45,000 items in a supermarket, more than a quarter contain corn. Pollan meditates on the freakishly protean nature of the corn plant and looks at how the food industry has exploited it, to the detriment of everyone from farmers to fat-and-getting-fatter Americans. Besides Stephen King, few other writers have made a corn field seem so sinister.

Later, Pollan prepares a dinner with items from Whole Foods, investigating the flaws in the world of "big organic"; cooks a meal with ingredients from a small, utopian Virginia farm; and assembles a feast from things he's foraged and hunted.

This may sound earnest, but Pollan isn't preachy: he's too thoughtful a writer, and too dogged a researcher, to let ideology take over. He's also funny and adventurous. He bounces around on an old International Harvester tractor, gets down on his belly to examine a pasture from a cow's-eye view, shoots a wild pig and otherwise throws himself into the making of his meals.

I'm not convinced I'd want to go hunting with Pollan, but I'm sure I'd enjoy having dinner with him. Just as long as we could eat at a table, not in a Toyota. (Apr.)